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| Guizien, Katell; Orvain, Francis; Duchene, Jean-claude; Le Hir, Pierre. |
| The average bed shear stress and bed friction factor of samples with any roughness was derived from the head loss between upstream and downstream of a test section in an erosion tunnel. The method was validated in both hydraulically smooth (plexiglass; Reynolds number less than 25,000) and rough regimes (calibrated particles with known roughness). As a first step toward using this method on natural sediment, this method was tested with experimental mesocosms assembled from field collected materials (sieved sediments; diatoms). Bed shear stress measurement precision was high enough in the experiments to detect a positive significant relationship between bed friction factor and core roughness. The observed bed friction factor increase could be related to... |
| Tipo: Text |
Palavras-chave: Bed roughness; Friction factor; Mud beds; Biological activity; Erosion experiments. |
| Ano: 2012 |
URL: http://archimer.ifremer.fr/doc/00117/22807/20617.pdf |
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| Rocha,Hermes S. da; Marques,Patricia A. A.; Camargo,Antonio P. de; Frizzone,José A.; Saretta,Ezequiel. |
| ABSTRACT Assuming that a roughness meter can be successfully employed to measure the roughness on the internal surface of irrigation pipes, this research had the purpose of defining parameters and procedures required to represent the internal surface roughness of plastic pipes used in irrigation. In 2013, the roughness parameter Ra, traditional for the representation of surface irregularities in most situations, and the parameters Rc, Rq, and Ry were estimated based on 350 samples of polyvinyl chloride (PVC) and low-density polyethylene (LDPE) pipes. Pressure losses were determined from experiments carried out in laboratory. Estimations of pressure loss varied significantly according to the roughness parameters (Ra, Rc, Rq, and Ry) and the corresponding... |
| Tipo: Info:eu-repo/semantics/article |
Palavras-chave: Friction factor; Head loss; Roughness meter. |
| Ano: 2017 |
URL: http://www.scielo.br/scielo.php?script=sci_arttext&pid=S1415-43662017000300143 |
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